DTMsim - DTM channel simulation in ns

Dynamic Transfer Mode (DTM) is a ring based MAN technology that provides a channel abstraction with a dynamically adjustable capacity. TCP is a reliable end to end transport protocol capable of adjusting its rate. The primary goal of this work is investigate the coupling of dynamically allocating bandwidth to TCP flows with the affect this has on the congestion control mechanism of TCP. In particular we wanted to find scenerios where this scheme does not work, where either all the link capacity is allocated to TCP or congestion collapse occurs and no capacity is allocated to TCP. We have created a simulation environment using ns-2 to investigate TCP over networks which have a variable capacity link. We begin with a single TCP Tahoe flow over a fixed bandwidth link and progressively add more complexity to understand the behaviour of dynamically adjusting link capacity to TCP and vice versa

The effect of lenders’ credit risk transfer activities on borrowing firms’ equity returns

Although innovative credit risk transfer techniques help to allocate risk more optimally, policymakers worry that they may detrimentally affect the effort spent by financial intermediaries in screening and mo-nitoring credit exposures. This paper examines the equity market’s response to loan announcements. In common with the literature it reports a significantly positive average excess return – the well known ‘bank certification’ effect. However, if the lending bank is known to actively manage its credit risk ex-posure through large-scale securitization programmes, the magnitude of the effect falls by two thirds. The equity market does not appear to place any value on news of loans extended by banks that are known to transfer credit risk off their books.bank loans; credit derivatives; bank certification

Select Committees are engaging better than ever before, but while much as been accomplished, much more remains possible

Select Committees in the UK Parliament have become more powerful over the last five years or so since the implementation of the Wright Commission reforms, which allowed for – amongst other things – the election by the whole House of Commons of members and chairs. Here, Ian Marsh looks at the outreach of the committees since these changes, finding examples of good practice and unfulfilled potential. He concludes that while a great deal has been done, there is potential for far more

How contemporary politics became trapped in the short term and whether it can be repaired

Ian Marsh argues that policy convergence, cynical marketing strategies and the demise of party organisations have destroyed the infrastructures that once provided a platform for longer term policy debates. Contemporary politics is trapped in short-termism and parties may never be able to recover

Twelve recommendations to strengthen public engagement by Commons committees

Since the Wright reforms which strengthened the independence of select committees against the government and party front benches were implemented, committees have improved their visibility and policy impact. Here, Ian Marsh reports 12 recommendations to strengthen the public engagement by committees to improve their impact and visibility further

Bank behaviour with access to credit risk transfer markets

One of the most important recent innovations in financial markets has been the development of credit derivative products that allow banks to more actively manage their credit portfolios than ever before. We analyse the effect that access to these markets has had on the lending behaviour of a sample of banks, using a sample of banks that have not accessed these markets as a control group. We find that banks that adopt advanced credit risk management techniques (proxied by the issuance of at least one collateralized loan obligation) experience a permanent increase in their target loan levels of around 50%. Partial adjustment to this target, however, means that the impact on actual loan levels is spread over several years. Our findings confirm the general efficiency-enhancing implications of new risk management techniques in a world with frictions suggested in the theoretical literature.credit derivatives; bank loans; moral hazard

Dimensioning Links for IP Telephony

Transmitting telephone calls over the Internet causes problems not present in current telephone technology such as packet loss and delay due to queueing in routers. In this undergraduate thesis we study how a Markov modulated Poisson process is applied as an arrival process to a multiplexer and we study the performance in terms of loss probability. The input consists of the superposition of independent voice sources. The predictions of the model is compared with results obtained with simulations of the multiplexer made with a network simulator. The buffer occupancy distribution is also studied and we see how this distribution changes as the load increases

Delivering Public Services: Locality, Learning and Reciprocity in Place Based Practice

Policymakers across myriad jurisdictions are grappling with the challenge of complex policy problems. Multi-faceted, complex, and seemingly intractable, ‘wicked’ problems have exhausted the repertoire of the standard policy approaches. In response, governments are increasingly looking for new options, and one approach that has gained significant scholarly interest, along with increasing attention from practitioners, is ‘place-based’ solutions. This paper surveys conceptual aspects of this approach. It describes practices in comparable jurisdictions – the UK, the EU and the US. And it explores efforts over the past decade to ‘localise’ Indigenous services. It sketches the governance challenge in migrating from top-down or principal-agent arrangements towards place-based practice. The paper concludes that many of the building blocks for this shift already exist but that these need to be re-oriented around ‘learning’. Funding and other administrative protocols may also ultimately need to be redefined